Create an easy to use java script software program to replace an existing excel spreadsheet

I currently have a budget spreadsheet using google sheets that forecasts the next 12 months profit and loss and breaks it down into individual months. It allows the user to adjust scenarios (i.e. revenue increase by 15% or adding 2 new employees etc) to understand how it will effect the bottom line. Once the forecast has been entered, the spreadsheet breaks it down into monthly increments to be used a s a budgeting and comparison tool. Finally, when the month actually occurs, it allows the user to compare their budget with actual so they can learn from the variances that occurred. I use it as a training tool for small business owners to understand how to read and truly understand their profit and loss statement. I have proven the effectiveness using it on many companies (and growing). The spreadsheet is a bit cumbersome and I want to simplify it with the idea of making it a web based software eventually however the first version doesn't necessarily need to go that far (it would be helpful if it were created in a way that would allow for an easier transition into an eventual web based software).